Fine-coarse tuning drive utilizing ball bearing type gearing to couple shafts



A. P. WEINER 3,188,872 FINE-COARSE TUNING. DRIVE UTILIZING BALL BEARINGJune 15, 1965 TYPE GEARING TO COUPLE SHAFTS Flled MaI'Oh 22, 1963 FIG-3INVENTORz ALBERT P. WEINER, Wj.

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United States Patent O 3,l8i,872 ZtUltlllNG BREVE UTEMZENG BALL EEAHHNG'lli/PE GEARENG T0 CQUEME SHAFES Albert l. Weiner, Syracuse, NX.,assigner to General Electric Company, a corporation of New York FiledMar. 22, 1953, Ser. No. 2o7,`l5 5 Claims. (Cl. i4-1952) This inventionrelates to signal channel selecting means for a continuously tunableconverter and more particularly to a means for coupling coarse andtuning forces to adiustable elements of electrical tuning components inthe converter.

A continuously tunable converter is one of a type adapted for selectingeach of a plurality of successively higher or lower signal channelsWithin a desired band of frequencies. Known mechanisms for performingthis function have included an operator control knob which may besmoothly actuated through the band Without intermediate detent actionWithin the limits ot' the band.

ln one form of conver er, continuously tunable selection of a desiredsignal channel is provided by a plurality of electrical components eachhaving adjustable elements thereof operatively coupled to an actuatingshaft. An electrical characteristic of each or the components is alteredin accordance with a variation in the position of the shalt. As anillustrative example, in one type of continuously tunable converterarrangement, signal channel selection is provided, in an Ultra l-lif'hFrequency band, by circuits comprising transmission lines Which are endtuned by capacitive electrical components. The capacitive componentsinclude adjustable rotor elements mounted on an actuating shaft. One endof this shaft, hereinafter referred to as the rotor shaft, extendsthrough a wall of an enclosure for the converter to an exterior pointand is thus accessible for coupling a rotational tuning force thereto.

Many continuously tunable converters are adapted for selectively tuningrelatively high signal frequencies. For example, a UHF converter for usewith television receiving apparatus is required to select signalfrequencies within the presently allocated band of 470 mc. to 890 mc.Because of the relatively high frequency of operation, the converteritself generally represents a source of undesirable radiation. Althoughother spurious frequencies are radiated, the higher levels of radiationare at the fundamental frequency of a local oscillator or harmonicsthereof. A high degree ol care is consequently required in thearrangement of both electrical components and structural elements inorder to reduce the radiation,

ln particular, the exterior extending end of the aforementioned rotorshaft has proven to be a relatively high level radiator. For reducingundesirable radiations from the shaft, it has been proposed to positionit Within the enclosure and to provide means for coupling a tuning forcefrom a point without the enclosure to the shaft. Force coupling meanswhich have heretofore been provided to perform this function arerelatively complex, expensive, and at times may even act as a radiator.

ln view of the relatively large frequency bands which a converter isrequired to tune, as in a television receiver, and the generallyrelatively small bandwidth of a selected channel, means are provided forboth coarse and line tuning the converter to desired channels. The meansfor iin-e tuning the converter generally comprise mechanical arnrangements for reducing the angular rotation of the rotor shaft withrespect to its angular rotation when an equivalent coarse tuning angularrotation is imparted thereto. These arrangements have been relativelycomplex, cumbersome in mounting on the converter enclosure, consequentlyexpensive, and not readily adaptable to the miniaturization of theconverter.

Accordingly, it is an object of the present invention to provideimproved coarse and line tuning means for a continuously tunableconverter.

lt is another object of the present invention to provide an improvedmeans for coupling coarse and line tuning forces from a point Without acontinuously tunable converter enclosure to a rotor shaft positionedtherein.

Another object of this invention is to provide relatively uncomplex andinexpensive means for coupling operative coarse and line tuning forcesto an enclosed rotor shaft in a continuously tunable converter.

Another obg'ect of this invention is to provide, in a continuouslytunable converter having an enclosed rotor shaft, a force coupling meansfor coupling an operative coarse and line tuning force to the shaft yetwhich does not contribute signiiicantly to undesirable radiation fromthe converter.

Still another object of this invention is to provide a continuouslytunable converter having coarse and line tuning means includingrelatively uncomplex and inexpensive means for readily mounting thetuning means on an enclosure for the converter.

A further object of this invention is to provide a relatively compactcoarse and iine tuning means which contributes to a miniaturization oithe converter.

The generally very high frequency of operation of a converter,especially UHF converters, dictates that the arrangement and spacing ofelectrical and mechanical components be made with a high degree of care.Heretofore, when a converter enclosure was mounted to other apparatus,as for example the chassis of a television receiver, the enclosurebecame, at times, distorted due to tolerances and variations in mountingholes and brackets. This distortion caused a variation in the criticalspacing of the components and resulted in an adverse effect upon theoperation oi the converter. This adverse effect would be especiallynoticeable in miniaturized converters.

Thus, it is another object of this invention to provide means formounting a converter' enclosure to other electrical apparatus and whichreduces distortion of the enclosure upon mounting.

Another object of the invention is to provide relatively uncomplex andinexpensive means for mounting a converter enclosure to other apparatus.

Another object or the invention is to provide a coarse and line tuningforce coupling arrangement having integral means for mounting the tunerenclosure to other apparatus.

A further object is to provide relatively uncomplex means for mounting aminiaturized converter to other apparatus.

Appearance requirements for consumer electrical apparatus, such as atelevision receiver, at times dictate the coaxial positioning of coarseand line tuning knobs which are made available for viewer adjustment.Prior arrangements for providing coaxially positioned knobs for acontinuously tuned converter have been relatively complex, expensive,and unsuitable to miniaturization of the converter and reduction in sizeof the overall apparatus.

provided in a continuously tunable converter for coupling coarse and netuning forces from a point without an enclosure of the converter'Y to arotor shaft positioned therein. The coupling means includes acoarsetuning drive shaft having an end thereof extending into theenclosure and means for coupling a rotary motion, which is imparted -tothe drive shaft, to the rotor shaft. VA tine tuning shaft is coaxiallypositioned Ywith the drive shaft and is coupled'to the drive shaft byrotary motion speed reduction means. The speed reduction means comprisea ball-planetary arrangement. Mounting means are Vprovided for housingthe drive and fine tuning shafts and for positioning the shafts on theenclosure.V

A resilient means is provided for both cooperating with the mountingmeans inv securing the mounting means to the converter enclosure and forproviding spring loading for a thrust bearing of the force couplingmeans.

Means are also provided for cooperating with the mounting means formounting the converter enclosure to otherapparatus.

Further objects, features and the attending advantages of the inventionwill be apparent with reference to the following specifications anddrawings in which:

FIGURE 1 is af View of a converter enclosure, partly cut away, andillustrating a rotor shaft anda tuning force coupling means of thepresent invention mounted in an operative position thereon, Y

FIGURE 2 is a partial perspective View of the converterenclosure ofFIGURE 1 illustrating a force coupling means mounting aperture,

FIGURES is an assembly view, partly in sectional form, ofthe tuningforce coupling means of the present invention illustrating the forcecoupling means mounted to a wall of the converter enclosure, and

FIGURE 4 is an exploded view of the tuning force coupling means of thisinvention. Y t

In FIGUREV 1, a metal converter enclosure 11 is illusi trated. Onlythose portions ofthe enclos-ure and con- Vverter are illustrated whichare believednecessary for a complete understanding of the presentinvention. Various other detailed views of the enclosure 11 along withelectrical components mounted therein and a circuit arrangement of thecomponents for selecting signal channels in a UHF band are described incopending applications Serial No.v 267,275, filed March 22, 1963andlmounting a coarse and fine tuning force coupling means The mountingaperture 33 is best seen in FIGURE 2. ,Al-

thereto Vas is vindicatedrin Vmore detail hereinafter.y

though a slotted aperture 33 is illustrated, it' will become evidentfromthe following description that the aperture may assume various otherconfigurations.

An electricallyY conductive rotor shaft 35 is rotatably-` mounted withinthe enclosure by any suitable bearings,

indicated generally in FIGURE 1 as 37 and 39. Thev present invention isto provide Y I Associated capacitive stator elements 43 are alsoillustrated and are coupled to other electrical components for tuningthe other components Vand thereby selecting a desired signal channel.Theother electrical components may comprise transmission lines, notshown, positioned in the compartments 25, 27 and 29 and which are endtuned'by the Vcapacitive Vcomponents forV providing frequency selectionand conversion;

' A drive gear 45 is mounted on a segment of the rotor shaft in the gearcompartment 31. The gear 45 may be mountedby any conventional means suchas a press lit.

Although a single spur gear 45 is illustrated, various welly known geararrangements having back-lash reduction means may be substituted for the`gear 45.

Referring now more particularly-to the subject of the present invention,tuning force coupling means are provided and are'illustrated in detailin FIGURES 3 and 4. The force coupling means comprises a coarse tuningdrive shaft 51, a ine tuning shaft 53, and a bushing for housing theshafts 51 and 53.

The drive shaft 51 is tubular and is adapted to be axially positionedwithin the body of the bushing 55 as indicated in FIGURE 3. A rotarycoarse tuning force is coupled directly to the shaft 51 by a controlknob, not shown. The knob can be positioned coaxially with the shaft andcoupled thereto, at slots 57. A gear 59 is also ,provided` and mounted'on an end segment 61 of the shaft 51 for coupling thel rotary motion ofthe shaft to the rotor shaft 35. The gear 59 is secured by a pin 53which is wedgedin a hole 65 in the gear and a hole 67 in the segment 61.AThe shaft 5 1 when assembled with rother elements of the force couplingmeans is positioned in the aperture 33 of enclosure 11 in amanner forproviding extension of theI segment 61 into the gear compartment 31 andengagement of the gear 59'with gear 45.

The tine tuningrv shaft 53 is adapted to be axially positioned within acavity of the tubular shaft 51. f A rotary ne tuning force is coupleddirectly to the shaft 53 by a control knob, not shown. The knob may bepositioned coaxially with the shaftv 53. and coupled thereto at a groove69.k

VIn accordance with a'feature of the present invention, rotary Amotionspeed reduction means are provided. To this end, the coarsey and finetuning shafts 51 and 53 are arranged in a manner for .coupling a netuning force from shaft 53 toy 51 but at a reduced angular rotation.

yIn particular, shaft 53 includes a relatively narrow neck segment 71.The neck segment cooperates with va pair of balls '73, which extend fromthe segment 71 and through a pair of holes 75 in shaft 51 to makefrictional contact with a tapered inner surface 77 in the bushing 55,for coupling a'rotary fine tuning force from shaft 53 to shaft 51. Shaft51 is thereby caused to rotate but at the planetary rate of rotation ofthe balls which is less than that Vof shaft 53. This speed reduction isdetermined by the circumference of the bushing 'surfaceA 77 and by thecircumference ofthe neck'segment71.' Thus, arcoaxial twoV speed drivearrangement is described for providing l continuous tuning selection ina converter.

Vwithin the bushing V55 -is limited by contact between the rotor shaftextends through the compartments 25,727, 29

and 31 and has mounted thereon at positions within the compartments 25,27 and 29 rotor elements 41 of capacitive tuning components. vTheelements 41 may be mounted by anyconventional means such'as a press tit.

In assembled form, axial travel of the shafts 51 and 53 balls 73l andthe tapered'innersurface 77 of the bushing and by a washer 79 which ispress tted into a groove 81 i in shaft 51.' Y

meansfcomprising a clip 85 for mounting and securing the force couplingmeans to the enclosure 11.v The clip 85 may be comprisedY of anysuitablel spring material and includes a U-shaped segment k87, a angesegment 89, and a third segment 91. Ridge 83 `has an outer diametergreater than the dimensions 93 of aperture'33 of enclosure 11-while amain body portion of the bushing 55 has a diameter less than the`dimension 93. The bushing may be atesora ge E positioned in theaperture 33 and axial passage to the right as viewed in FIGURE 3 isinhibited by contact between the inner surface of wall 17 and ridge 83.The U-shaped segment 87 of clip 85 is positioned in a straddling mannerabout the main body portion of bushing 5S on the outer side of wall 17,flange segment 89 extends across the wall I7, and flange 91 extendsdownward and contacts a thrust ball bearing 95 which is positioned in acup shaped bearing surface 97 on shaft 53. The assembly is mounted andis secured in position by the cooperation of the integral ridge 83 ofbushing 55 and the spring clip 8d. In addition, flange segment 91 ofclip S5 provides advantageous spring thrust loading for the shaft 53.

Although the ridge 83 is described as circular and having a diametergreater than dimension 93, the ridge may assume other configurations asmay also the aperture 33. For mounting and securing the assembly incooperation with the clip 85, the bushing must have an appurtenance andthe aperture must have a configuration which will limit axial motion ofthe bushing through the aperture.

In accordance with an additional feature of the invention, the bushingincludes a main body portion having a threaded outer surface which incooperation with locking means, shown to comprise nut 99, operates formounting and securing the enclosure 11 to other apparatus. The otherapparatus need only have an aperture through which the bushing mayextend. The nut 99 is threaded on the bushing from an opposite surfacefor securing the enclosure 11 to the apparatus. A nut 99 is shownpositioned on the bushing in FIGURES l and 3 while in practice, asurface of other apparatus would be positioned between the segment 87and the nut 99.

It can be seen in FIGURE 1 that the mounted shafts terminate in the gearcompartment 31. The metallic wall 23 operates to reduce capacitive andinductive coupling between the shafts and elements within the oscillatorcompartment 29. The gear 59, which is preferably of a nonconductivematerial, inhibits conduction of electrical energy via shaft 35 to theforce coupling means. Thus, by my arrangement, undesirable radiation iskept to a minimum.

I have described a relatively uncomplex and inexpensive means forproviding coarse and tine tuning for a continuously tuned converter. Inaddition, the arrangement I have described features relatively simplemeans for mounting the tuning means to a converter enclosure and formounting the enclosure to other apparatus.

While I have illustrated and described and have pointed out in theannexed claims certain novel features of my invention, it will beunderstood that various omissions, substitutions and changes in theforms and details of the system illustrated may be made by those skilledin the art without departing from the spirit of the invention and thescope of the claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A means for providing continuous coarse and fine tuning for aconverter comprising: a converter having an enclosure, said enclosurehaving an aperture therein; a rotor shaft rotatably mounted in theenclosure; a gear mounted on said rotor shaft for rotation therewith; atubular bushing having an inner surface including a tapered ball bearingsurface segment and a shaft bearing surface segment; resilient clipmeans for mounting said bushing in said enclosure aperture; a tubularcylindrical coarse tuning drive shaft having an aperture located in awall thereof; a drive gear mounted on a segment of said shaft; saiddrive shaft positioned in said bushing for providing axial alignment ofsaid shaft aperture and ball bearing surface and extension into saidenclosure for engagement of said drive and rotor shaft gears; acylindrical fine tuning shaft having a neck segment thereof ofrelatively less circumference than a circumference of a main bodyportion; said fine tuning shaft positioned in a tubular portion of saidcoarse tuning drive shaft for providing axial alignment between saidneck segment and said shaft aperture; said resilient clip means alsoproviding thrust loading for said coarse and said fine tuning shafts; aball bearing disposed between said neck segment and shaft aperture andpartially extending through said shaft aperture for making frictionalcontact with said ball hearing surface; means for coupling a coarsetuning force to said coarse tuning drive shaft; and means for coupling ane tuning force to said fine tuning shaft.

2. A means for providing continuous coarse and ne tuning for a convertercomprising: a converter having an enclosure; said enclosure including agear compartment, a wall bordering said gear compartment, and anaperture in said wall; a rotor shaft segment positioned in the gearcompartment for rotation therewith; a tubular bushing having an innersurface including a tapered segment and a cylindrical bearing surfacesegment, a main body portion having a threaded outer surface, and anintegral appurtenance; said bushing positioned on said enclosure in amanner for providing extension of said main body portion through saidaperture and an abutment of said appurtenance with a surface of saidwall; a tubular cylindrical coarse tuning drive shaft having a pluralityof apertures located in a wall thereof; a drive gear mounted on asegment of said drive shaft; said drive shaft positioned in said bushingin a manner for providing axial alignment of said shaft aperture andsaid tapered segment of said bushing and the extension of said gearmounting segment into said gear compartment and engagement of said drivegear with said rotor gear; a cylindrical ne tuning shaft having a necksegment thereof of relatively less circumference than a circumference ofa main body portion thereof; said tine tuning shaft positioned in atubular portion of said coarse tuning drive shaft for providing axialalignment between said neck segment and said apertures in said driveshaft; a plurality of ball bearings disposed between said neck segmentand said plurality of apertures in said drive shaft and extendingtherefrom for providing frictional contact with said tapered surface; amounting clip having a U-shaped segment, a segment substantiallyparallel to said U-shaped segment and a flange segment; said clippositioned on said enclosure and about said bushing in a manner forsecuring said bushing to said enclosure and for providing spring thrustloading for said drive and fine tuning shafts; locking means forcooperating with said threaded outer surface of said bearing formounting said enclosure to other apparatus; and means for couplingcoarse and fine tuning forces to said coarse drive and tine tuningshafts respectively.

3. In a continuously tunable converter having an enclosure for theconverter, an aperture extending from a first surface to a secondparallel opposite surface in a wall of the enclosure, a rotor shaftrotatably mounted in the converter and a rotary drive arrangement forcoupling a tuning force to the rotor shaft, a means for mounting saiddrive arrangement to the enclosure comprising: a bushing for housing andpositioning said drive arrangement on said enclosure; said bushinghaving a main body portion thereof and an integral appurtenance; saidbushing positioned on said enclosure in a manner for providing extensionof said main body portion through the aperture beyond the first surfaceand abutment of said appurtenance with the second surface; and amounting clip for securing said bushing to said enclosure, said clipcomprising a unitary structure of resilient material having a U-shapedsegment, a flanged segment joined t0 said U- shaped segment andsubstantially perpendicular therewith, and a third segment joined to andextending away from said flange segment and toward said U-shapedsegment, said clip positioned on said enclosure in a manner forproviding that said U-shaped segment straddles said main body portionand said third segment exerts anaxial force f References Cited by the'Examinery on saidrbushing'forrnaintaining lcontact between said UNITEDSTATES PATENTS appurtenanceV and said -second surface. Y

4. The apparatus of claim S'Wherein said third segment gile;"'f of saidclipV contacts the rotary drive arrangementhoused 5 2034327 3/36 Bussard74' 10`52 in Said bushing for Providing thrust loading OHhEdfV? 2,039622V5/36 Bennett 74-1o52 @rangement- V y 2,095,279 10/37 Newman 'ne-10.52

5. The` apparatus of clalrn 4. wherein sa1d1ma1nbo`dy V2,103,517 12/37De Taf 74. 1052 portion has afthreaded external surface for mountingsaid enclosure to other apparatus. in cooperation With thread 1K0engaging means. Y HERMANKARL SAALBACH, Primary Examiner.

1. A MEANS FOR PROVIDING CONTINUOUS COARSE AND THE FINE TUNING FOR ACONVERTER COMPRISING: A CONVERTER HAVING AN ENCLOSURE, SAID ENCLOSUREHAVING AN APERTURE THEREIN; A ROTOR SHAFT ROTATABLY MOUNTED IN THEENCLOSURE; A GEAR MOUNTED ON SAID ROTOR SHAFT FOR ROTATION THEREWITH; ATUBULAR BUSHING HAVING AN INNER SURFACE INCLUDING A TAPERED BALL BEARINGSURFACE SEGMENT AND A SHAFT BEARING SURFACE SEGMENT; RESILIENT CLIPMEANS FOR MOUNTING SAID BUSHING IN SAID ENCLOSURE APERTURE; A TUBULARCYLINDRICAL COARSE TUNING DRIVE SHAFT HAVING AN APERTURE LOCATED IN AWALL THEREOF; A DRIVE GEAR MOUNTED ON A SEGMENT OF SAID SHAFT; SAIDDRIVE SHAFT POSITIONED IN SAID BUSHING FOR PROVIDING AXIAL ALIGNMENT OFSAID SHAFT APERTURE AND BALL BEARING SURFACE AND EXTENSION INTO SAIDCLOSURE FOR ENGAGEMENT OF SAID DRIVE ROTOR SHAFT GEARS; A CYLINDRICALFINE TUNING SHAFT HAVING A NECK SEGMENT THEREOF OF RELATIVELY LESSCIRCUMFERENCE THAN A CIRCUMFERENCE OF A MAIN